Steering mechanism



Aug. 25, 1936. c. s. BRAGG 2,051,816

STEERING MECHANISM 7 Original Filed Dec. '7, 1951 4 Sheets-Sheet 1 ggxxg Wm INVENTOR IG. 7 BY Caleb 5 Bragg 1 =4 1 7-1 I T: 1 02 2. 6

ATTORNEY Aug. 25, 1936. C s 'BRAGG 2,051,816

STEERING MECHANISM Original Filed Dec. 7, 1931 4 Sheets-Sheet 2 IN V EN TOR;

Caleb 5. fire 9 ATTORNEX Aug. 25, 1936. c. s. BRAGG STEERING MECHANISM I 4 Sheets- Sheet 5 Original Filed Dec.- '7. 1931 m m m m Caleb 5. Br gg ,4 ram Aug. 25, 1936. c. s. BRAGG 2,051,816

S TEERING MECHANI SM Original Filed Dec; 7, 1951 4 Sheets-Sheet 4 n Is f .1 x C I b gym.

a a Q 0 Q gi Y aif A TTORNEY Patented Aug. 25 1936 UNITED STATES PATENT OFFICE STEERING MECHANISM Caleb s. Bragg, Palm swam,

orto

Original application December I, 1931, Serial No.

Divided and this application February 5, 1934, Serial No. 709,696

6 Claims. (Cl. l$--79.2)

This application is a division of my copending application Serial No. 579,399 filed December 7, 1931, which has matured into Patent No. 1,952, 034, which has been reissued as Reissue 19,515.

This invention relates to steering mechanism,

and more particularly to such mechanism applicable to automotive vehicles.

In the operation of automotive vehicles of the heavier types, such as large and powerful passenger cars, motor busses, motor. trucks, and the like, the vehicles are steered ordinarily by turning a pair of wheels simultaneously by means of a hand-operated wheel controlled by the driver. When the'vehicle is passing over a hard smooth l5 roadway and proceeding in a substantially straight direction, the operation of this steering wheel or other manually controlled device does not ordinarily require the exertion of any considerable physical force on the part of the driver,

20 but in making turns and sudden swerves, especially at slow speed, as in city traillc, the operation of such manually operated devices calls for the exertion of much greater force, even on substantially smooth roads, which in the operation 25 of city busses, trucks, and the like, produces exhaustion after continuous driving. In the operation of the. vehicle on the ruttyor soft roads, or when as very frequently happens, the outer wheels of the vehicle are necessarily turned on to 30 lateral portions or a roadway, which are rutty or soft, a very great amount of force is required for operating the'steering mechanism correctly. However, the steering effort required to deter-- -mine the direction of the moving vehicle is, at 5. worst, much less fatiguing than the effort required when the vehicle is at rest. Here, we introduce problems of static friction between the many movable parts of the steering mechanism as well as between the tires and the ground, and in general 40 static friction is greater than the purely dynamic friction incurred during the motion 01' the ve-' hicle; for example, with a vehicle parked against the curb it is usually vary diflicult to turn the vehicles wheels and with the vehicle mired in the mud the available physical strength to break the hold upon the wheels is usually-completely inadeuate.

q The problem of steering when the vehicle is at rest is also aggravated by the increasing practice of carrying more of the pay load upon the front axle of the heavier vehicles, such, for example, placing the driver's cab over the motor and so permitting the pay load to be carried several feet v nearer the front axle. This practice results in in- .10

creasing the steering efiort beyond the physical strength and endurance of the operatonwithin steering wheel ratios that are practical and safe.

An important object of my invention is, therefore, to provide, inconnection withthe ordinary steering mechanismof such automotive vehicles, 5' or any automotive .vehicle in which its use may be found advantageous or desirable, a power actuator for positively actuating'the steering mechanism of the vehicle, even when the latter is at rest, and under the positive and delicate control 10 of the operator through the ordinary steering wheel or other manually operated device.

It is a further object to so arrange the actuator with respect to the steering mechanism of the vehicle that the latter may be directly and entirely 15 operated by the" manually operated mechanism when the conditions are such as torequire but a small amount of the physical eii'ort of the driver to either eiiect the movement of the steering, mechanism, or resist road shocks; The construction is such, however, that the power of the actu-,

atcr may be instantly called into operative eilfect. to supplant the aforementioned minimum of physical force exerted by the operator and to thereby relieve him from the labor of operating the steering mechanism whenever steering conditions become hard or whenever a great amount of power is required to be applied to the steering mechanism.

My invention also provides means whereby, whenever the actuator is furnishing its maximum power to effect a steering movement of the steering mechanism, the physical force exerted by the operator may be concurrently added to that exerted by the actuator, and further whereby, upon the entire failure of the actuator for any reason, the steering mechanism can nevertheless be manually controlled and operatedin the usual manner.

In one arrangement 1 of the aforementioned parts there is provided, in conjunction with the conventional drag link and its operating crank arm extending from the chassis side rail, a valve operating lever member pivotally connected to and supported on the crank arm. The lever member is preferably arranged, at one of its ends to either operate or be operated by the drag link and/or a power actuator. The lever is further provided, adjacent its other end, with yieldable means contacting the'aforementioned crank arm and at its extreme-end with means for actuating the control valve of the actuator. The parts are so constructed and arranged that relative movement between the arm and lever, with the collapse of the yieldable means, serves to actuate the control valve to. thereby energize the power actuator.

50 oil pressure, and to this end there is suggested controlled by a pressure regulating valve,

the various bearings of the engine, from which the oil finds its way back to a sump or reservoir and is used over and over again. In order to maintain an adequate supply of oil under pressure for lubricating all conditions of the oil, which becomes thin when heated or from use, and under all conditions of the bearing surfaces, which when worn permit a greater amount of oil to pass through them, it is customary to supply a pump of far greater capacity than normally needed. In conjunction with such a pump itis also customary. to insert, in the pressure line from the pump, a by-pass leading back to the sump or reservoir which will maintain a desired maximum pressure in the circulating lubricating system by opening sufi'iciently to by-pass the excess oil back to ,the reservoir or sump.

This valve is ordinarily of the adjustable spring loaded ball type, and in order to provide sufli'cient lift to the valve to permit a large volume of oil to pass when the motor is running at high speed and toprevent the motor from smoking when idling the ball is ordinarily slightly unseated at minimum pump pressures. This leakage obviously reduces the minimum pressure, which pressure is obtained during the idling of the engine; however, it is during the lower engine speeds that the greatest demands are placed upon the steeringmechanism. This is particularly true with the vehicle parked ormired as heretofore described.

We are, therefore, confronted with the problem of normally having. an insufliciency of oil pressure at. the very time when it is desired. to effectively operate the power actuator.

It is, therefore, one of the principal objects of the invention to step-up the idling motor the ,retention, of the aforementioned conven- 'tional pressure regulating valve and the addition of a secondary or auxiliary pressure regulating valve cooperating therewithas described below..

According to my invention the conventional valve is left intact in the system but is 'sufficiently loaded to obviate rupture of the lubri-.

cated engine parts and functions as such only during the operation of the power actuator. At all other times, that is with the actuator inoperative, the auxiliary valve referred to functions as the normal maximum pressure regulating valve of the engine, serving inthe place of the.

. aforementioned usual engine valve, and-is furthermore arranged to be automatically closedroif or isolated fromthe system when. and if the power actuator is rendered operable. Such an arrangement of parts insures, when and if the.

actuator is brought into operation, an increased minimum engine oil pressure over and above that obtained by the; conventional setting for the idling engine.

sure permits the employment of a smaller actuthe various bearings, under 'tality, of a manually operated control valve, actuate the steering mechanism of an automotive vehicle.

- invention Figure 9; and

Figures 14. and 15 disclose, in section, details of the control valve in-its cracked and lapped provided with steering wheels indicatedat The increased operating pres-.

ating cylinder, reducing the time required to effect the'power steering.

One suggested arrangement contemplates the mounting of the aforementioned auxiliary valve inseries with the control valve for the actuator, with the latter in its neutral position, which position is such as to maintain the actuator inoperative and at the same time place the auxiliary valve in direct-commumcation with the engine lubricating system. The parts are furthermore so arranged that operation of the'control valve, which is preferably of the slide type, serves to cut-out the auxiliary valve and thereby automatically throw the entire burden of relieving the system of excess pressure upon the stepped-up main or conventional. regulating val've.

The invention in its broadest aspect, therefore, contemplates the employment of the force feed'lubricating system of the engine, modified to permit an increase of the minimum pressure of said system, as a source of power for'actuation of a power actuator orservo motor, the latter being rendered operative, and the lubricating system being modified, through the instrumen- Other objects of the invention and meritorious advantages thereof will become apparent from a.'reading of the detail description of the in the specifications to follow taken in connection with the accompanying draw,-

ings, in which:

Figure l discloses, tional parts of an automotive vehicle togetherwith my invention in'corporatedtherein;

Figure 2 discloses, in side elevation, the most essential, parts of the invention in cooperation with the drag link of the conventional steering mechanism;

,Figure' 3 discloses the elements of- Figure 2 just after the valve is cracked;

Figure 4 discloses the same parts during the operation of the power actuator;

Figure 5 is a detail sectional view taken on line 5-5 of Figure 2;

Figure 6 is :a detail sectional view of the actuator control valve and pressure regulating .valve cooperating therewith together with. a schematic view of theengine lubricating system; v Figures 7 and 7c are detail sectionalviews of the control valve during its operation;

Figure 8 is a view similar to Figure 1 disclosing a modification of my invention;

Figures 9, 10, 11 and 12 are views similar to Figures 2 to 5,'incl usive, disclosing the features of the modification;

diagrammatically, conven Figure- 13 is a sectional view or the modified form'of actuator and is taken on line i'3l3 of shown the ordinary manner of mounting and connecting the same for joint actuation, although it is to be understood that my invention'is applicaconnection with these steering wheels 'I have ble to any form of'steering mechanism. In the present instance thewheels are mounted on stub axles l4 forming with their bearings- IS the, usual steering knuckles, semi axle being provided with a steering arm I! and said arms being connected by a tie rod 26 int'he usual manner. One of the axles is provided with the usual steering. lever 22 to which the usual drag link 24 is connected in any tion 30 cooperatingto rotate the shaft 32, Figure 5, the latter being provided with a downwardly extending arm 34. The arm 34 is interconnected with the drag link, the piston of a power actuator and with a valve mechanism therefor, all as more clearly described hereinafter, and in such manner that the steering mechanism can be operated either with or without the assistance of the actuator by turning the steering wheel 26.

To this'end the arm 34.is provided with a lever member 36 pivotally mounted thereon at 33.- The lever 36 is preferably forked at its lower end, one arm 40 being provided with a stub shaft 4| pivotaliy connected at 42 to one end of the drag link and the remaining arm 43 is pivotaily connected at 44 to the operating or connecting rod 46 of a power actuator generally indicated at 46, Figure 1. At its upper endthe lever is provided with laterally extending projections 50 provided attheir outer ends with inwardly extending cars 52 having threaded openings receiving adjustable stops 54 contactible at their inner ends with stops 56 projecting from the' arm 34. Compression springs 58 may be interposed between the cars 52 and arm, the same being guided upon the aforementioned stops 54 and 56. Links 60 and 62 are pivotally connected at one of their ends to the ends of the arm and lever, respectively, and

at their remaining ends to a bar 64 pivotally connected, at its center, to a link 68 connected to and adapted to actuate a valve mechanism for the power actuator, which mechanism will be described in greater detail hereinafter. The particular arrangement of the links as described obviates movement of the rod 66 with the arm and lever moving as a unit.

With the parts in their inoperativeposition as disclosed in Figure 2, the springs 58 are suflicient-ly strong to maintain the lever 36 in alignment with the arm 34 and thereby maintain the valve in its neutral position; when compressed to their full extent, however, the springs permit stops 5d and 56 to contact, at once obviating further and harm-, ful movement of the valve mechanism and also providing for a direct manual application of the steeringmechanism.

From the description of the parts thus far given, it will be seen that when the hand wheel 26 is turned in one direction or the other the arm 3% will be moved either forwardly or rearwardiy, as the case may be, and that if the resistance of the supported on its opposite sides by brackets 72' secured to the chassis side rail 74. Such a mounting permits the actuator piston 16 and its rod 46 to be connected directly to the drag link in aligirment with the axis of its pivotal connection with the lever 36, thereby obviating universal joints or equivalent construction. The relative movement of the interconnected parts during the operation of the power mechanism as well as during the movement of the vehicle is thus compensated for.

The valve mechanism for controlling the operation of the actuator is disclosed in detail in Fig- II, rigidly secured to the chassis, and housing a slidable piston member 69 connected by red 63 to the bar 64 as heretofore described. The valve (parts are shown in the off or neutral position in 'ures 6 and 7 and preferably comprises a casing 34 and lever 36, the latter fulcruming on the drag link 24 at 42. This movement, however, presupposes suflicient resistance to movement of the steering mechanism to collapse the spring 56, all as heretofore described, and clearly disclosed in Figure 3. The aforementioned relative movement of the arm and lever causes a differential movement of the links and 62 to move the link 68 to the left, Figure 3, and crack the valve to energize the actuator in the manner more fully described hereinafter. v

The power fluid for energizing the actuator is preferably derived from the force feed lubricating system of the engine, and to this end an inlet port 82 in the valve is placed in continuous circuit with the oiling system of the engine, shown diagrammatically in Figure, 6. This system preferably comprises a conventional pump 84 continuousiy forcing oil, from sump 66 and under pressure, to the engine parts .88, the conventional nism, all as clearly disclosed in Figure 4. The

liquid forced from the actuator during this working stroke of the pistonwill. be returned to the sump via conduit lllll, ports '96 and H12 in the valve casing and conduit I03. j

The movement of the piston', during the operation of the steering mechanism by power, will follow the movement of, the hand wheel 26 so long as the latter is turned with suflicient force to keep-the lever spring 56 compremed and the valve cracked. If the force from the piston is inadev quate to move the wheels, or move them fast enough, thephysical efiort of the operator may .be added to that of the piston,"the lever 36 and arm 35 acting as a; unit under such physical force, the position of the parts, considering this phase of the operation, also being disclosed in Figure 4. As clearly disclosedythe operation is double-acting or reversible, and once the wheels have been turned to their new position it is merely necessary to reverse the direction of movement of the hand wheel, as with manual steering, to

. obtain a power return of the mechanism tothe straight ahead position of the wheels. The position of the valve parts, during the power steering of the wheels to the right, is disclosed in detail in Figure 7a, the pressure fluid passing out is through port 88 and returned to the sump via ports 84, I04 and duct I08 in the valve. In the neutral position of the valve the ends of the cylinder are connected with each other and with the sump, so there is no resistance to the movement of the, piston by manual steering, the 011 moving from one end of the cylinder to the other.

There is disclosed in Figures 8 to 15, inclusive, a modified form of power actuator and valve mechanism. This structure comprises a doubleended cylinder I08 having a piston I08 connected by rod IIO to the lower end of a valve actuating lever II2.- Lever H2 is pivoted to arm H4 at H8 and is also provided with the operating springs II8 and other cooperating lever structure as previously' described. Lever H2 is pivotally connected at H3 'in coaxial alignment with the pivot I of arm II4, to valve operating rod I22, the latter being universally connected to a lever I24 :fulcrumed at I28 on the supports for the actuator cylinder. By positioning the pivot II3 opposite pivot I20 unitary movement of the arm H4 and lever II2 has no effect on the valve mechanism.

Lever I24 is recessed at its end to house the ball end of a lever member I28 pivotally mounted at I30 upon a valve housing I32 extending from II2, Figure 10, serves to crack the valve by registering either of ducts I38 or I40 with an inlet port I42 in the actuator in communication with the aforementioned lubricating system of the engine by means of flexible conduit I44 and with one or the other of ducts I45 in the actuator. Figure 14 discloses the valve in its cracked position.

The piston is thus moved, Figure 11, under the pressure derived from the engine pump, to actuate .the steering mechanism and/or resist road shocks, the liquid on the non-pressure side of the piston being forced back to the sump via one or the otherof ducts I38 or I40 into the valve and thence through conduit I48. If movement of the hand wheel is stopped, the continued movement of the piston I08 will cause relative movement between the arm H2 and lever II4 to "lap the valve mechanism as disclosed in Figure 15, both of ports I38 and I40 in the valve mechanism behing blanked bythe slide valve. l'hepiston, to-

gether with'itsconnected steering mechanism, is thusheld rigidly, in position until the hand wheel is again movedto recrack the valve; As with the first described embodiment, the actuator is double-acting, facilitating the control and simulating conventional manual operation of the,

lubricating system. In such a system, in order to maintain an adequate supply of oil under pressure for lubricating the various bearings, it is customary to maintain the pump 04 at a capacity far greater than normally needed, the excess oil being returned to the sump under the control of maximum. This leakage obviously reduces the minimum pressure, which pressure is obtained .during the idling of the engine; however, it is during the lower engine speeds that the greatest demands are placed uponthe steering mechamsm. This is particularly true with the vehicle parked or mired as heretofore described.

There is thus an insuflicienoy of oil pressure at i the very time when it is desired to effectively operate the power actuator.

This defect is overcome, in the suggested construction, by abnormally spring loading the valve member in the valve 90. which'latter valve structure is a duplicate of the valve I48 of Figure 6. The loading is such as to insure a seating of the valve member I50, with the engine idling, and is also such as to permit operation of the valve to obviate rupture of the system at abnormal pressures, but only functioning when and if the actuator is brought into play as more clearly described hereinafter. Cooperating with the valve 90 there is provided the aforementioned valve I48, preferably mounted'on the control valve of the actuator. This valve comprises the aforementioned poppet member I50 urged into engagement with its seat, by'a spring I 52, the valve casing being provided with a port I54 intercommunicating with the sump via conduits I58 and I03. With the actuator control valve in neutral or ofP' position a bore I58 therein communicates with the regulating valve I48, and in this position the valve functions as the normalregulating valve of the engine lubricating system, the spring I52 being set to limit the pressure of the system to the maximum desired for satisfactory and economical lubrication.

As a further feature of the invention, the valve I48 is so positioned with respect to the actuator control valve that opening of the latter serves to 'cut off or isolate the valve I48 as clearly disclosed in Figures 7 and 7a. Such operation immediately throws the entire burden of relieving the lubri eating system of excess pressure upon-the valve 80, which, however. hasbeen stepped-up as described. The minimum oil pressure is thus increased permitting a more effective operation of the actuator during the idling of the engine. Such a pressure permits a reduction in size of the actuator piston with its attendant advantages.

Myinvention, therefore, provides a very flexible and easily controlled steering arrangement which can be very readily attached to the normal steering mechanism of automotive vehicles of any kind without making any radical changes .therein, and by the use of which the operator can exercise the fullest control of the steering wheels (1) under conditions which oppose only a slight resistance to the steering movement; (2) by power alone; (3) concurrently by physical eifort and by the power actuator; (4) exclusively by physical eil'ort upon the event of total failure of power; and (5) with a minimum of lost motion at steering wheel.

It is to be understood that while the illustrated embodiments of the invention are described as shown, a considerable latitude is to be provided in construction within the range of the appended claims.

I claim:

1. In an automotive vehicle provided with an engine forced feed lubricating system and a steering gear, a power actuator for operating said steering gear, a control valve for said actuator, safety and pressure regulating valves in said lubricating system, connections interconnecting said steering gear and control valve, and means including said connections whereby manual operation of the steering gear renders the actuator con. trol valve operative and renders one of the pressure regulating valves inoperative.

2. In an automotive steering mechanism including a power actuator and a control valve therefor, a drag link, a pivoted steering arm, manually operablemeans for actuating said arm and means for operating said control valve, said latter means adapted to transmit the power of said actuator to the drag link, said means comprising a link pivotally mounted, adjacent one of its ends,

upon one end of said steering arm, said link being of forked construction at one of its ends, connections between the forked end of said link and said actuator and drag link and other connections between the other end of the link and said control valve, said latter. connections including a bar member pivotally connected at its center to the control valve and spaced pai'allel links each connected at one of its ends to one end of said bar and each connected at its remaining end to the ends of the link and arm respectively.

3. For use with an automotive vehicle, a steering system comprising a power actuator, a control therefor, a main arm, a pivot therefor, an-auxiliary arm pivoted on the main arm and adapted at times to move as a unit with the main arm and at times to move about its pivot relative thereto,

said arms and to said actuator control and aligned with said pivot.

4. For use with an automotive vehicle, a steering system comprising a power actuator, a control therefor, a main arm, a pivot therefor, an

auxiliary arm pivoted on the main arm and ing a link connected to one arm, a second link connected to the other arm at a point equidistant from said pivot, and a cross bar pivotally connected to both of said links and to said actuator control.

5. In a hydraulic automotive steering mechanism for a vehicle having a motor, a drag link, a pivoted steering arm, a power cylinder, means for manually operating said steering arm, a valve for controlling the operation of said power actuator, a relief valve, means for operating said control valve, means whereby operation of said control valve renders said relief valve ineffective, and means for creating fluid pressure for actuating said power actuator and for lubricating the motor.

6. In a hydraulic automotive steering mechanism for a vehicle having a motor, a drag link, a pivoted steering arm, a double ended power cylinder, an auxiliary arm pivotally mounted on said steering arm, means for manually operating said steering arm, a valve for controlling the operation of said power actuator, a relief valve, means connecting said auxiliary arm with said drag link, means connecting said auxiliary arm with said power actuator, means connecting said auxiliary arm and said steering arm with said control valve whereby relative movement between said arms operates said control valve, means whereby operation of said control valve renders said relief valve ineffective, and means for creating fluid pressure for actuating said power actuator and for lubricating the motor.

CALEB s. BRAGG. 

